Late summer watering of Bermuda grass.
Once in awhile, especially in the summer months, I get asked, what is the best way to water my grass? This is a very good question, since most people’s beliefs are completely false. Here in Duncan Oklahoma, we have a few strains of Bermuda that are prominent. Bermuda grass is very heat tolerant, which makes it an excellent choice for a lawn grass in our climate. Even though Bermuda is a hardy and heat tolerant grass, even it needs a helping hand from us in the form of watering.
There are two very common misconceptions about watering Bermuda in our area. One is, that in the heat of the day the grass needs a “drink” to help ward off heat stress, especially when it is a hundred plus degrees. The other is that you need to water daily and in short intervals. I think both of these misconceptions are spawned by the fact that we try to project our “human needs” onto our grass. While for us humans it is VERY important to stay hydrated often especially in the hottest parts of the day, for Bermuda that just is not the case. I will address these misconceptions below.
1) The “Drink”: At first glance, as a human, it makes perfect sense that the lawn needs a refreshing drink in the heat of the day. After all, that’s what we need! The truth is that watering in the heat of the day is counterproductive not to mention costly. Studies have shown that up to 80% of water from sprinkler systems is wasted through evaporation during the heat of the day, in fact up to 50% of the water evaporates before it even hits the ground. Once what is left hits the hot grass and soil, another 30% can be lost to evaporation before it soaks into the ground. This doesn’t leave a lot of water left to get where it is actually needed, the roots. We are all acutely aware of how much our water bills are, and the price always seem to go up! Think about how much your last water bill was, now take 80% of that money and picture yourself throwing that out the window, because in essence that is exactly what you are doing if you water in the heat of the day!
Solution: The most optimal time to water is in the early morning hours right before sun up. This is when the air and ground temperature is at it’s lowest. This also gives the water time to soak into the ground before the direct sunlight has chance to start the evaporation process.
2) Watering in short daily intervals: Like the “Drink” misconception, watering daily in short intervals seems to make sense. However, this misconception too is false and in some cases even illegal! Since the beginning of summer here in Duncan Oklahoma, we have been in a stage two watering restriction. This stage two restriction essentially only allows us to water every other day with no lawn watering at all on Sunday. Even short watering times every other day is not ideal for our grass. Short watering only allows the water to permeate a few inches of the top soil, when this happens Bermuda grass roots will stay within those few inches. Also, persistent watering can lead to the development of fungus and other diseases. For Bermuda grass to be lush and thick, not to mention drought, insect, and disease tolerant, the roots need to be much deeper. The ultimate goal of irrigating our lawns is to keep them healthy and looking good, deep roots is key to this.
Solution: Watering intervals are unique to each lawn, no two lawns are the same. However, a general guideline for Bermuda grass is to water until the soil is wet to the depth of 6 inches. Once the soil is watered to this depth, you do not need to water again until the grass starts to show symptoms of drought stress. The signs of drought stress are as follows, a dull bluish color, rolled or folded leaves, and persistent footprints when walked on. As soon as these signs develop it is time to deep water again. Following this procedure will encourage deep root growth, once this is accomplished your lawn will look and be healthy.
In my next blog post, I will go into some procedures you can use to make sure you are irrigating to the right depth.